Method of making u-shaped pipe-bends.



N G.- PEANDSEN. METHOD OF MAKING U-SHAPBD PIPE BENDS,

Patented Mar. 23, 1915 A PPLIGATION FILED JAN. 12, 19 .4.

Ylrqxl.

R m V W if. ll llfl li II I WITNESSES g wr 5 0 A m F m P m U M 0 u M 1,133,017. Original application filed April 5, 1912,

Erm-

NIELs CHRISTOPHER FRANDsEu', or COPENHAGEN, DENMARK ASSIGNOR To SCHMIDTSCHE HEISSDAMPF oEsELLsoHArras 3a.,

HOHE, GERMANY, A conrona'rxou or GERMANY. I

OF CASSEL-WILHELMS- METHOD OF MAKING USHAPED PIPE BENDS.

; To all whom it mo concern:

Be it known that I. 'NiELs Cunrs'rornnn "FnA'NpsEN, a subject of the King: of Den "mark, residing at Copenhagen, in the Kingdom of Denmark, have invented a new and useful Improvement in Methods of Making U-Shaped Pipe-Bends, of which the follow- ;in,q is a specification.

My invention relates to I a method by means ofwhich two pipe ends mavihe so shaped that they can at once, be welded together to constitute a single pipe united by a UI-shaped pipe'hend. Mv invention has esp'ecial utility in the manufacture of superheater pipes for smoke tube super-heaters, such pipes generally l'la'VlIlQ two or more ad ja'cent lees united hv U-shaped bends.

Mvinvention will be better understood by referring to the drawings accompanying in Which i FlLlllQ -1 rc esents an end elevationloi a preferred torn. of a die. hv means of which the method may he practised; Fig. 2 represents a section ta en alone the line 2-2 of Fiq. 1. a pipe end being shown siiu; Fig.

. 31 represents on a smaller scale the die opened as isreouired for the removal of a formed pine end: Fig. 4: representsin cenpositioned for .to he formed .tral longitudinal section a pipe end ready Fig. 5 represents in section two formed pipe ends as they appear when welding or after being welded. the section being taken in the plane of the pipes; and Fig. 6 represents in section, a'complcte pipe bend having its points reinforcedl Essentially. the die embodies a hodv portionicomnrisine' two, preferablv substantially similar hinsred sections each of which is scooped out in the form which half of a pipe end is to have after it is bent. The two sections of the die being closed together, provision is made for an inner horn or nandrel attached to the die to be swung into that portion of the die which represents the bend of the completedpipe end in such a way as to constitute a core spaced away from the die walls (2'. e. the walls of the i scooped out portions) so that the pipe end when suitably heated and forced into the Specification of Letters Patent.

PatentedMar as, 1915.

Serial No. 688.649. Dividedand this applicationflled January 12,

1914. Serial No. 811,558. Y

die will be bent into the required curve between the horn and said die-walls.

My invention will be better understood exactly conform in configuration to the shape of a. finished pipe end.

A separate piece H extending beyond the.

top and bottom of the combined and closed: die sections, is provided with tongues F which closely embrace the die when the two halves are thus closed together. These tongues are suitably cut away so as to en gage journals E fixed to thetw'o halves of the die. The piece H has attached to it. midway between the tongues F a curved horn or mandrel D so positioned that when the piece H with its tongues F is rotated upon the atoresaid journalsE, this horn will reg ister with the curved portion of the die in the region corresponding to the tube end so as to be substantially concentric with but s aced from the curved walls of the die. hen the hornis thus positioned. a flat bolt M is slipped through suitably located holt holes G which have been formed both in the tongues F and in the two die halvesA and B so that said two halves and the horn D are rigidlv locked together.

My method is practised as follows: A pipe end of diameter corresponding to the scooped out portion of the die is sawed off at an angle L (Fig. 4). bis pipe end is then heated to a red heat and forced into thestraight portion of the die-opening N (Fig. 2) so that the point L of the tube end will strike the curved portion of the die at I this will cause the pipe endyif'sufiicient pressure curved portion of ,the die opening between the wall thereoiandthe. horn D. If it is be applied, to bebent jaround .the

complished by having the scooped out portion of the die in this region enlarged to any desired extent, as shown for example by the dotted line N, Fig. 2. By suitablydehning this region of enlargement, the wall thickness of the finished pipe end may be made to lessen gradually from a maximum at the point of the pipe end to a normal thickness at any chosen distance from said point end. Fig. 6 shows a finished pipe bend thus reinforced. This reinforcing is very desirablev in super-heater pipes in order that they may withstand the heat of the furnace gases which is most intense at the points of the-U bends lying adjacent to thefire box. A single pipe end having been formed as above described, thebolt M is knocked out and the iece H with its tongues F rotated upon the Journals E so as to withdraw the horn D from the die opening. A suitable number of pipe ends having been formed, they may then be joined together in pairs as indicated in Fig. 5, and the ends welded in any convenient manner.

I have described my invention as practised with a die for forming one pipe end at a time, but dies providing for bending a number of pipe ends simultaneously may easily be arranged.

As described the die is operated by hand but it may, if preferred, be operated by power within the scope of my invention.

This application is a division of my prior application entitled Die for making U- shaped pipe bends, Serial Number 688,649, filed April 5, 1912.

Having described my invention, 1 claim:

1. The improvement in the art of making- U-shaped pipe bends which comprises taking a piece of straight pipe, applyingaxial and lateral pressure to opposite end walls thereof soas to both compress and bend the end of the pipe and simultaneously maintaining anoutward pressure upon the inside,

of the end wall of the pipe.

2. The improvement in the art of making U-shaped pipe bends which comprises talc ing a piece of straight pipe, heating the end thereof, applying axial and lateral pressure toopposite end walls thereof so as to both. compress and bend the end of the pipe and simultaneously maintaining an outward pressure upon the inside of the end wall of the pipe.

3. The improvement in the art of making U-shaped pipe bends which comprises taking a piece of straight pipe, cutting ofi said pipe so as to have. an elliptical section, applying axial pressure to the Wall about the circumference of the ellipse and lateral pressure to the pipe end in that plane of the pipe which includes the major axis of the ellipse so as to both compress and bend the end of the pipe and simultaneously mains taining an outward pressure upon the inside of the end Wall of the pipe.

4. The improvement in the art of making U-shaped pipe bends which comprises taking a piece of straight pipe, cutting off said pipe so as to have an elliptical section, heating the end thereof, applying axial pressure to the wall about the circumference of the ellipse and lateral pressure to the pipe end in that plane of the pipe which includes the major axis of the ellipse so as to both compress and bend the end of the pipe and simultaneously maintaining an outward pressure upon the inside of the end wall of the pipe.

5. The improvement in the art of making U-shaped pipe bends which com-prises taking a piece of straight pipe, cutting ofi' said pipe so as to have an elliptical section, applying axial pressure to the wall about the circumference of the ellipse and lateral pressure to the pipe end in that plane of the pipe which includes the major axis of the ellipse and in a direction which will bend the pointed end of the pipe toward the axis of said pipe so as to both compress and bend the end of the pipe and simultaneously maintaining an outward pressure upon the inside of the end Wall of the pipe. v t

In testimony whereof T'have hereunto set my. hand in the presence ofj two subscribing witnesses.

NIELS CHRISTOPHER FRANDSEN. [L. 8.]

r I l/lfllZIleSS-GS:

JOSEPH ROBERT VVENK, Carr. RUDOLPH ALFRED Jaconson. 

